Solution: Count and Say
Understand how to solve the count and say sequence problem by tracking consecutive digits and applying run-length encoding. Learn to iteratively build each term from the previous one, improving efficiency and clarity. This lesson helps you develop skills to handle string processing patterns in coding interviews.
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Statement
The “count and say” is a sequence of strings built by describing the previous string:
The sequence starts with
countAndSay(1) = “1”For
n > 1,countAndSay(n)is created by run-length encoding the stringcountAndSay(n - 1).
Run-length encoding (RLE) works by grouping identical consecutive characters and replacing each group with the count of characters followed by the character itself. For example, the string “15224” is read as: one 1, one 5, two 2s, and one 4, producing “11152214”.
Given a positive integer n, return the
Constraints:
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